Multiple fuse plug



July 10, 1934.

Filed Oct. 19, 1931 ur/ 7% v H Patented July I0, 1934 UNITED STATES PATENT OFFECE 1 Claim.

My invention relates to fuse plugs and has for its object to provide a new and efficient fuse plug which will be so constructed as to have a multiple fuse adapted to have the cap of the fuse turned and engage a new fuse section after one fuse has been melted out by a short circuit or an overload in the line.

A further object is to provide a multiple fuse plug which will be so constructed as to provide one which has the cap rotatable to change the fuse and which will be so insulated that there will be no possibility of a short circuit therein or of more than one fuse coming into use at the one time.

A still further object is to provide a fuse plug which will have the cap rotatable to turn new fuses into place and which cap will be provided with means to prevent it turning in any direction but the proper one,

of securing the multiple fuse in place in the plug, and to provide a simple economical device which will meet the requirements of the public in economical price.

These objects I accomplish with the device illustrated in the accompanying drawing in which similar numerals and letters of reference indicate like parts throughout the several views and as described in the specification forming a part of this application and pointed out in the appended claim.

In the drawing in which I have shown the best and most preferred manner of building my invention Figure 1 is a side elevation of the fuse plug complete.

Figure 2 is a plan view thereof.

Figure 3 is a section on line 33 of Figure .4.

Figure 4 is a plan view of the base of the plug with the top portion and the fuse elements removed.

Figure 5 is an inverted view of the fuse element.

Figure 6 is a side elevation thereof showing the method used in making the contact and in preventing the cap from rotating the wrong di- ,rection.

Figure 7 is a plan view of the multiple fuse element used in the device before bending and crimping it to fit in the plug.

Figure 8 is a side elevation of the plate carrying the fuse element.

Figure 9 is a side elevation of the central contact spring.

Figure 10 is a modified form of making the cen- A still further object is to provide a new method tral contact in the form of a coil spring with the spring to hold the top engaged with the central portion of the fuse element.

In the drawing I have shown the fuse as made of a body of non-conducting material A, having a medial hole or bore 1 therein and having the exterior of the lower smaller portion 2 of the body formed as threads 3 therearound. The eX terior of the top of the said body is grooved at 4 leaving a flange 5 around the top side thereof. A hole 6 is formed in the said body substantially parallel to the bore 1, but on one side thereof, said hole 6 having the bottom end curved out and opening out through the side wall of the body A. The exterior of the hand engaging portion B of the body A is castellated all around as at '7 with one fiat portion 8 directly above the opening hole 6 and the flat portion will have some printed letters indicating that the contact is directly in alignment therewith, so that the person operating the fuse can tell through which opening to look for the broken burnt out fuse and know when he has changed by rotating the fuse head to a new fuse contact.

Into the bottom end of the body A I then insert the central contact post 9, which contact post is formed with a spring body having the bottom 10 provided with an extension bar 11 therebelow, said extension to fit into a socket 13 of the end contact 12 and the fit cf the two being close enough to make a driving fit hold the two together securedly. To make a secure fit a drop of solder may be placed in the socket before the extension 11 is driven into the socket 13. The contact 12 passes up through a medial hole in the body A into the bore 1. The top end of the contact post 9 is bent in'wardiy at M and a semispherical end 15 formed thereon with the spherical portion upward A contact member 16 is then soldered to a screw body 17 and the screw body is screwed onto the threads 3 of the body A and the contact 16 is passed up through the hole 6. The top end of the hole 6 is extended into a rectangular socket 6a and the top end of the contact 16 is bent at right angles to the upright T and the end is formed into a curved spring member 18, said spring member having the end 19 bent up to engage the rotating plate of the device and to make contact with the fuse segments as they are brought into contact therewith. The end of the member 19 is square to engage the slots in the rotating member to prevent the member from rotating in the wrong direction. The rotating plate C of the device which holds the fuse elements is formed of a circular plate of insulating material 20 having radial slots or grooves 21 cut therein extending to the perimeter from a central post 22, which post is formed on the bottom side of the plate. The end of the post is cut out into a concave form 23 to receive the medial portion of the fuse element and to have the said medial portion formed to fit therein. Fuse sight openings or holes 24 are bored through the plate with the axis of the holes in alignment with the central line of the slots so that when the fuses are in the slots the thin ection may be viewed through the openings 24. Slots 25 are cut through from near the ends of the grooves out of the top to allow for securing the ends of the fuse elements. One side of the grooves 21 is out in a slanting edge 26 to allow the end 19 of the contact 16 to pass thereover without undue friction and the other side of the groove is at right angles to the face so that the end of the contact will engage squarely therewith. The multiple fuse F of the device is made of radially extending fuse members 29 formed from. a circular central hub 30. The members -29 are formed thin at 31 for the point of break when an overload is on the line and the ends 32 of the members are thickened where they engage the grooves 21, and the extreme end of the ends 32 is passed up through the slots 25 and the end is crimped down over the top side of the plate C holding the fuse securely therein. The portions 33 of the fuses which is that portion from the hub to the thin portion as bent up the sides of the post 22 with the thin portion extending out therefrom over the sight openings. A cover G is then provided for the entire device formed of a top plate having a hexagonal or round hole or sight opening 35 through the top and having the sides thereof serrated to form easy hand engaging means. The lower edge of the sides is bent inwardly around the flange 5 to hold the top and plate thereto. A sheet of mica 36 is carried in the cover between the cover and the plate C to insure against gasses entering the device and to prevent and chance of short circuits, or from the operator getting a shock when using the device.

In assembling the device the metal thread is screwed onto the base and the contact 16 placed down through the hole 6 with the end 18 fitting into the hole 6. Solder is then dropped on the joint between the two to secure them together. The central contact 9 is placed in the bore 2 and the contact 12 driven onto the end of the extension 11 thereby securing the central contact in the base. The plate C is then placed on the base with the fuse element secured thereto as herebefore described with the end of the post covered by the central hub 30 of the fuse element" and the fuse is in constant contact with the semispherical contact 14 making a contact from the base contact 12 through the contact 9 to the fuse. The ends 32 of the fuse are so positioned that one of them is in contact with the end 19 of the contact 16 thereby completing the circuit through the fuse. The spring end 18 of the contact 16 holds the end 19 against the section 32 of the fuse by spring pressure and insures a permanent contact therewith until turned by the user. The circuit travels through the central contact 12, through the contact 9 to the hub of the fuse and thence out to and through the contact 16 by the end 19 to the screw of the base. The end 19 prevents the device from being turned in the wrong direction by engaging the sides of the grooves 21.

The operation of the device is as follows:

When an overload is on the wires the fuse in contact with the spring 19 will blow out leaving the circuit broken. To again make a complete circuit the operator turns the cover and plate thus turning a new section of the radial fuse into contact with the spring 19 of the contact thereby completing the circuit again.

Having thus described my invention I desire to secure by Letters Patent and claim:

In a fuse plug of the class described the combination of a non-conducting base having a screw thread on the lower end thereof; a central bore therein and a socket formed in and through one side thereof; a flange around the top of said base; a fuse carrying plate carried on top of said base; radial fuse elements formed around a concave shaped central hub and carried in grooves in said plate; means to pass the ends of said fuse elements through slots near the ends of the grooves in said plate to secure the fuse elements therein; a post in the center of said plate having a concave end thereof to engage a similarly shaped hub of the fuse; a metal thread screwed onto said base; a spring contact secured thereto and passing up through and into said socket in said base, the end of said spring contact being bent back upon itself to engage one of said fuse elements and to prevent backward rotation of said fuse element and plate; a central contact post secured through the bottom of said base and having spring pressure semi-spherical contact thereon to engage the concave hub of said fuse; a sheet of mica over said contact plate; and a cover adapted to crimp into the flange of said base to hold the entire device together with the mica separating the cover from the plate.

CLARENCE I. JUSTHEIM. 

